CN201821114U - Automatic reactive power compensation device for voltage regulating substation - Google Patents

Abstract

The utility model relates to a voltage regulating type automatic reactive power compensation device of a transformer substation. The device comprises an isolating switch, a control device, an SVR automatic voltage regulator, a reactor and a capacitor, wherein, the isolating switch, the SVR automatic voltage regulator, the reactor and the capacitor are electrically connected front and back in series with one another; secondary control circuits of the isolating switch and the SVR automatic voltage regulator are respectively connected with the control device; a capacitor bank comprises a fuse, the capacitor and a discharge coil; the fuse is connected in series with the capacitor; the fuse, the capacitor and the discharge coil are connected in parallel; and the terminal voltage of the capacitor is divided into 9 gears between 6 kV to 10 kV. The device solves the frequency moving problem of circuit breakers of 6 kV, 10 kV and 35 kV, reduces the impact of switching inrush current on a system, increases the power factor, reduces system loss, increases the equipment utilization rate, and can also be used for improving and upgrading old transformer substations.

Description

Automatic reactive power compensation device for voltage regulating substation

Technical field:

The utility model relates to a reactive power compensation technology of a substation.

Background technique

At present, the reactive power compensation devices used in substations mostly use circuit breakers to switch capacitors, or use vacuum contactors to switch capacitor banks in groups. The following problems generally exist: the power factor does not meet the specified requirements; over-compensation or under-compensation often occurs: over-compensation of the input capacitor, serious under-compensation of no input; operation overvoltage and closing inrush current, low utilization rate of the compensation device, and short service life of the equipment.

The current actual situation is, for example: for a 6300KVA main transformer in a 110KV/10KV substation, the capacitors configured in the substation are 3000kvar collective, and all of them are put in as soon as they are put in, and all of them are removed when they are cut off; Maintenance or even replacement, moreover, it can only be used occasionally in June, July, and August every year, the idle rate of capacitors reaches 90% of the time each year, and the available time is only 10%; the perennial reactive power deficit fluctuates between 1200-2500kvar, sometimes it can To 3200kvar, the average power factor is only 0.70, which is a serious waste.

Utility model content

The purpose of this utility model is to overcome the deficiencies of the prior art, and use the principle of "the output reactive power is proportional to the square of its terminal voltage" in the reactive power compensation of the capacitor bank to realize reactive power compensation, that is, to use SVR The automatic voltage regulator changes the terminal voltage of the capacitor to adjust the output of capacitive reactive power.

The utility model is achieved in that:

It is mainly composed of isolating switch, control device, SVR automatic voltage regulator, reactor and capacitor bank. The isolating switch, the SVR automatic voltage regulator, the reactor, and the capacitor bank are electrically connected in series; the secondary control circuits of the isolating switch and the SVR automatic voltage regulator are respectively connected to the control device.

The capacitor bank is composed of a fuse, a capacitor and a discharge coil, the fuse and the capacitor are connected in series, and the fuse, the capacitor and the discharge coil are connected in parallel. The fuse plays the role of protecting the capacitor; the role of the discharge coil: one is to discharge the capacitor after the equipment is cut off, and the other is to form a zero-sequence voltage to protect the capacitor.

The terminal voltage of the capacitor can be lowered from 10KV to 6KV, and can be adjusted in sections, that is, it can be adjusted in 9 gears between 6KV-10KV, and each gear can be raised (or lowered) by 0.5KV, such as 3000kvar. The power output can be adjusted to between 1080-3000kvar. That is to say, every time the SVR automatic voltage regulator changes gears, the terminal voltage of the capacitor will change accordingly, as follows:

When the first gear voltage is 6KV, the reactive power Q＝1080kvar;

When the second gear is 6.5kv, Q=1267.5kvar;

When the 3rd gear is 7kv, Q=1470kvar;

When the 4th gear is 7.5kv, Q=1687.5kvar;

When the 5th gear is 8kv, Q=1920kvar;

When the 6th gear is 8.5kv, Q=2167.5kvar;

When the 7th gear is 9kv, Q=2430kvar;

When the 8th gear is 9.5kv, Q=2707.5kvar;

When the 9th gear is 10kv, Q=3000kvar.

It can be seen that this device realizes fine reactive power compensation, changing level 1 compensation to level 9 compensation,

When the information collected by the control device shows that the required reactive power is greater than the upper limit of reactive power, the SVR boosts the voltage and increases the terminal voltage of the capacitor to increase the reactive power output; when the reactive power is lower than the lower limit of reactive power, the SVR steps down to reduce the reactive power of the capacitor. Work hard.

The utility model is beneficial in that:

1. Fine reactive power compensation, improve power factor, reduce system loss, improve main transformer transmission capacity, stabilize system voltage, improve equipment utilization; avoid 6KV, 10KV, 35KV circuit breaker frequency problem, reduce the impact of closing inrush on the system ; Protect the equipment in the station and prolong its electrical life. For enterprises, it can stabilize the working voltage, improve equipment utilization, and improve power factor.

2. Connect the SVR automatic voltage regulator in series between the circuit breaker in the station and the capacitor bank, through the comprehensive analysis of the voltage, current and reactive power information collected by the controller, automatically control the action of the vacuum on-load tap changer, and adjust the capacitor in a timely manner The terminal voltage of the capacitor changes the capacitive reactive power output by the capacitor.

3. Breaking through the traditional control mode, instead of directly using the circuit breaker or vacuum contactor to control the input or removal of the capacitor bank, but using the SVR automatic voltage regulator to shift gears to achieve fine reactive power compensation, changing the level 1 compensation to level 9-18 compensate. This device can be used in the transformation and upgrading of old substations to realize automation, full digital intelligent control, and comprehensive communication methods such as RS232, RS485, GPRS, etc.; it can meet the unattended requirements of new substations; it can also reduce the frequency of circuit breakers in the station , which is conducive to the stable and safe operation of the system.

Description of drawings

Fig. 1. the application schematic diagram of the utility model in substation;

Fig. 2. The schematic circuit diagram of the utility model embodiment.

Detailed ways

Describe an embodiment below in conjunction with accompanying drawing, the utility model is described further.

Fig. 1 shows the application of this embodiment in the substation

Take the dual main transformation of 110KV or 35KV substation as an example to illustrate:

According to the operating status of the main transformer in the substation, the control device collects the voltage and current signals of the main transformer and the bus voltage on the low-voltage side of the main transformer, and calculates the reactive power shortage of the substation through microcomputer processing, and controls the reactive power shortage of the substation at a certain level. Within the range, the tap-changer gear position signal of the SVR automatic voltage regulator is also collected at the same time, and the gear position of the SVR automatic voltage regulator tap-changer is driven to increase or decrease according to the current gear position and the calculated reactive power deficit of the substation. At the same time, according to the state of the circuit breaker: when the gear of the SVR automatic voltage regulator is adjusted to the lowest position, if the amount of reactive power overcompensation is too much, the control device will drive the circuit breaker to control and cut off the entire device. When the reactive power deficit of the substation is greater than the reactive power upper limit set by the control device, control the SVR automatic voltage regulator to boost the voltage-increase the terminal voltage of the capacitor to increase the reactive power output; if the reactive power gap is less than the control device setting When the lower limit of reactive power is reached, the SVR automatic voltage regulator steps down to reduce the reactive power output of the capacitor.

Fig. 2 shows the circuit principle of the utility model embodiment

Since the capacitance of the capacitor bank is constant, the reactive power output by the capacitor bank varies with the applied voltage. Assuming that the capacitor bank SVQR is connected to the system as shown in the figure, it first passes through the isolating switch. The transformer is an autotransformer that can vary between 60% and 100% of the rated voltage, which can adjust the terminal voltage of the back-end capacitor; then enter the reactor, the main function of the reactor is to suppress the harmonics of the substation. The hazards of capacitors, if the substation has no harmonics or is very small, the reactor can also be omitted; finally, it is commonly known as a capacitor bank composed of fuses, capacitors, and discharge coils: the fuse is mainly to protect the capacitor, and the function of the discharge coil is to act as After the equipment is cut off, the capacitor is discharged, and the second is to form a zero-sequence voltage to protect the capacitor.

The SVR automatic voltage regulator is connected in series between the circuit breaker and the capacitor bank, and the compensation capacity used to adjust the electricity at both ends of the capacitor bank is QCN (QCN is the rated capacity of the capacitor bank), and the voltage adjustment range of the voltage regulator is 0.6UCN～UCN( UCN is the rated voltage of the capacitor bank), the gear of the voltage regulator is 9 gears, and the output capacity of the capacitor bank is: the adjusted voltage of each gear is equal (5% UCN), then the output capacity of the capacitor bank corresponding to each gear is as follows:

Claims (2)

1. The automatic reactive power compensation device of the voltage regulating substation is characterized in that it is composed of an isolating switch, a control device, an SVR automatic voltage regulator, a reactor, and a capacitor bank; an isolating switch, an SVR automatic voltage regulator, a reactor, and a capacitor bank The front and back series electrical connection between them; the secondary control circuit of the isolating switch and the SVR automatic voltage regulator are respectively connected with the control device; Said capacitor bank consists of fuses, capacitors and discharge coils, the fuses and capacitors are connected in series, and the fuses, capacitors and discharge coils are connected in parallel. 2. The automatic reactive power compensation device of the voltage regulating substation according to claim 1, characterized in that: the terminal voltage of the capacitor is divided into 9 gears between 6KV-10KV, and each gear can be raised or lowered by 0.5 KV.

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